The curing or crosslinking of monomeric materials to produce thermoset resins is well known in the art. In general, the polymerizable monomers incorporate at least one and customarily more than one reactive group which serves as a site for the crosslinking or curing polymerization to produce the cured products. There are some polymerizable monomers wherein the active sites are such that the monomer will cure upon application of energy, e.g., heat or high intensity U.V. light. In many if not most cases, however, a curing agent is necessary to allow the curing reaction to take place at an acceptable rate. The curing agents are employed in catalytic or in stoichiometric amounts relative to the monomer to be crosslinked. The stoichiometric curing agents, i.e., those agents which are provided in a substantial amount (although not necessarily precisely stoichiometric) relative to the monomer to be cured are the more commonly used and are typically multi-functional polymerizable materials having a plurality of reactive groups capable of participating in a crosslinking polymerization. A mixture of the monomer and curing agent, generally referred to as a thermosetting resin composition, is then cured by application of heat with or without the presence of an accelerator which may be added to obtain an even more acceptable rate. The reactive groups of the curing agent are typically materials having functional groups which contain active hydrogen atoms, or the equivalent, or multiple bonds between adjacent atoms which may both be carbon atoms or may have one or both atoms which are not carbon atoms.
Certain of the thermosetting resin compositions have polymerizable monomers which are cyclic in chemical character. In Knowles, J. Appl. Polymer Sci., Vol. 10(6) pp. 887-8 (1966), there is disclosed the use of a spirodilactone as a curing agent for epoxy resins. The curing of the epoxy compounds is not accompanied by decrease in volume, possibly because of the opening of the spirodilactone ring during the curing process. The cured products from cyclic monomers are often characterized by a relatively high glass transition temperature in addition to strength, solvent resistance and dimensional stability in applications where the cured products are likely to encounter elevated temperatures. It would be of advantage to provide a novel class of thermosetting resins incorporating polycyclic monomers which cure by reaction with polyfunctional curing agents to provide cured, crosslinked thermoset resin products of relatively high glass transition temperatures and of other good properties.